The present invention relates to a film suction mechanism for a camera, and more particularly, to a film suction mechanism for a camera in which a film is held against a pressure plate to maintain it in good planarity.
A film suction mechanism is already known in which a film is held against a pressure plate at the same time as a shutter release operation or in conjunction with a shutter release operation of a camera so that a good planarity of the film can be maintained. As disclosed in Japanese Laid-Open Utility Model No. 159,325/1978, for example, a conventional film suction mechanism is separate from the camera, and is synchronized with a shutter release operation of the camera through an operating member in the form of a release cable. Such film suction mechanism suffers from the following disadvantages:
1. The suction mechanism which is separate from the camera results in a complex construction and an increased size, causing an increased manufacturing cost. PA1 2. Because the suction mechanism is arranged to project rearwardly of a rear lid, the resulting protruding arrangement makes it inconvenient to carry the camera and to contain it in a camera casing. PA1 3. Since the suction applied during a previous shutter release still remains effective on a film during the initial phase of a film winding operation, there results an increased film loading to cause a rubbing action between the film and pressure plate, whereby the film is susceptible to damage. PA1 1. since the suction unit is disposed within the camera and is arranged to be connected to film suction openings or grooves formed in the pressure plate only when the rear lid is closed, the structure is simple and compact, contributing to a reduction in the manufacturing cost; PA1 2. the film suction mechanism is entirely assembled within the camera and has no parts or members which project externally of the camera, thus substantially improving the portable use, containment and ease of operation; and PA1 3. the suction unit may comprise an air damper assembly which is used in a single lens reflex camera to absorb shocks which may be applied to a movable reflecting mirror. This avoids the need for the provision of a separate suction unit. In addition, the compressed air which is produced as the mirror moves down forces the film away from the pressure plate, avoiding any increased loading during the winding of an exposed film and the resulting vulnerability of the film.